train guns.
F. Compressor-wheel to check recoil, hove taut before firing.
G. Crank for running gun in and out.
H. Smoke-box of XV-inch (_Passaic_ class).
O. Officer at sight-hole.
P. Port-hole.
R. Port-stopper.
S. Sight-hole.

416. In the _Passaic_ class the ports for the XV-in. gun are only of
sufficient dimensions to allow the passage of the shot at such
elevations and depressions as were judged necessary: the gun being
fired entirely within the turret. In order to protect the crew of the
gun from the blast of the explosion, the smoke-box was devised, which
to a certain extent accomplished the desired object, but at the
expense of rapidity of loading.

417. In designing the _Tecumseh_ class it was decided to enlarge the
port, so as to allow the face of the muzzle to run out flush with the
exterior of the turret. The gun was therefore lengthened sixteen (16)
inches, and the muzzle turned down to the minimum size.

418. The contracted space within the turret rendered it necessary to
introduce additional mechanical aids in lieu of manual labor in
running out, loading, and checking the recoil.

[Illustration: MONITOR TURRET. D. Van Nostrand Publisher. Julius Bien,
pr.]

419. The exercise therefore conforms to the established exercise for
great guns only as far as circumstances will admit.

The gun is supposed to be run in, and not loaded.

420. WORDS OF COMMAND.

I. "PROVIDE THE GUN!"
II. "SERVE VENT AND SPONGE!"
III. "LOAD!"
IV. "PRIME!"
V. "ELEVATE!" (OR DEPRESS).
VI. "RUN OUT!"
VII. "TRAIN!"
VIII. "READY--FIRE!"
IX. "RUN IN!"
X. "SECURE!"

MANUAL EXERCISE.

(RIGHT GUN.)

II. "SERVE VENT AND SPONGE!"

421. Gun Captain serves, then stops the Vent. No. 3 passes to left of
muzzle. No. 4 receives the moist Sponge-head from 6, and, assisted by
3, enters it in the Bore and forces it down as far as the first
section. No. 6 passes the successive sections of the staff to 4 as
needed, and receives them from him as the sponge is withdrawn.

After the sponge is withdrawn, Captain serves the Vent with his
priming-wire, and again closes it.

III. "LOAD!"

422. No. 4 receives Cartridge from 5, to whom the box has been passed
by 13, assisted by 3, enters it in the Bore; receives Rammer-head and
successive sections from 6, and, assisted by 3, rams home. Nos. 3 and
4 fall back from the muzzle. Gun Captain serves the Vent to